直喷柴油机火焰浮起长度的数值模拟研究  

NUMERICAL STUDY OF FLAME LIFT-OFF LENGTH IN A DI DIESEL ENGINE

作　　者：赵昌普[1] 陈生齐[1] 孙强[1] 李艳丽[1] 

机构地区：[1]天津大学内燃机燃烧学国家重点实验室,天津300072

出　　处：《工程热物理学报》2009年第10期1791-1794,共4页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.50676067);中国博士后科学基金资助项目(No.20070420698)

摘　　要：采用三维CFD模型模拟了直喷柴油机缸内喷雾燃烧过程,模拟缸压曲线得到了实验的验证。通过高温区与喷嘴之间的稳定距离来确定柴油机火焰浮起长度,研究在不同进气条件下火焰浮起长度的变化情况。该模型成功地预测了火焰浮起长度随着初始进气压力的增大而减少,随着进气温度的升高出现先增大后减少的趋势。同时模拟了在不同EGR率下柴油机缸内燃烧情况,发现火焰浮起长度和燃料着火延迟时间都随EGR率的增加而增大。The spray and combustion processes in a DI diesel engine are simulated with a multi- dimensional CFD model, and the simulated in-cylinder pressure is in good agreement with the measured one. The flame lift-off length is determined with the stabilized distance between the high temperature zone and the nozzle exit, and the influences of different intake gas conditions on the flame lift-off length are investigated. With the CFD model we successfully predict that the flame lift-off length tends to decrease as the initial intake gas pressure is increased. With an increase in the intake gas temperature, the flame lift-off length presents a tendency to increase first and decrease afterwards. The model is also applied to simulate the combustion process in the diesel engine in different EGR rate conditions, and the computed results show that both the flame lift-off length and the auto-ignition delay time are increased with increase in EGR rate.

关 键 词：火焰浮起长度 数值模拟 喷雾液核长度 柴油机 

分 类 号：TK421.2[动力工程及工程热物理—动力机械及工程]